Financial Instruments (Fair Values Of Derivatives Instruments) (Detail) - USD ($) $ in Millions	Sep. 30, 2020	Dec. 31, 2019
Schedule of Cost-method Investments [Line Items] (Deprecated 2018-01-31)
Fair Value, Asset Derivatives	$ 2	$ 5
Fair Value, Liability Derivatives	77	38
Designated As Hedging Instruments [Member] | Interest Rate Swaps [Member]
Schedule of Cost-method Investments [Line Items] (Deprecated 2018-01-31)
Fair Value, Asset Derivatives	0	0
Fair Value, Liability Derivatives	72	27
Not Designated As Hedging Instruments [Member] | Foreign Exchange Contract [Member]
Schedule of Cost-method Investments [Line Items] (Deprecated 2018-01-31)
Fair Value, Asset Derivatives	2	5
Fair Value, Liability Derivatives	4	10
Not Designated As Hedging Instruments [Member] | Interest Rate Contracts [Member]
Schedule of Cost-method Investments [Line Items] (Deprecated 2018-01-31)
Fair Value, Asset Derivatives	0	0
Fair Value, Liability Derivatives	0	1
Not Designated As Hedging Instruments [Member] | Commodity Contracts [Member]
Schedule of Cost-method Investments [Line Items] (Deprecated 2018-01-31)
Fair Value, Asset Derivatives	0	0
Fair Value, Liability Derivatives	$ 1	$ 0